Kie server client load balancer uses wrong URL for next endpoints when first endpoint fails.
This can be observed in AbstractKieServicesClientImpl.invoke() [1]. First call is done using complete URL, but if the call fails then URL is replaced by URL of next endpoint. However this new endpoint URL doesn't contain path and query part of old URL [2].

[1] https://github.com/kiegroup/droolsjbpm-integration/blob/8fa542454070a68133854e2c11d67e09fcfe5e05/kie-server-parent/kie-server-remote/kie-server-client/src/main/java/org/kie/server/client/impl/AbstractKieServicesClientImpl.java#L800
[2] https://github.com/kiegroup/droolsjbpm-integration/blob/8fa542454070a68133854e2c11d67e09fcfe5e05/kie-server-parent/kie-server-remote/kie-server-client/src/main/java/org/kie/server/client/impl/AbstractKieServicesClientImpl.java#L810